Density Calculator

Frequently Asked Questions

What is the density formula?

ρ = m/V (density equals mass divided by volume). SI units are kg/m³, but g/cm³ is common. Water density is 1000 kg/m³ or 1.0 g/cm³ at 4°C.

Why do some things float and others sink?

An object floats if its average density is less than the fluid's density. Steel sinks in water but a steel ship floats because the hull traps air, lowering average density.

How does temperature affect density?

Most substances expand when heated, lowering density. Water is unusual: it is densest at 4°C, which is why ice floats and lakes freeze top-down.

How can I measure an irregular object's volume?

Use water displacement: submerge it in a graduated cylinder and measure the rise. Then divide its mass by that volume to get density.

Provided by AllCalculators.io
Free online calculators for everyday. No registration required.

Estimates for informational purposes only.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.

JavaScript is required to use the interactive calculator above. The questions and answers below remain readable without JavaScript.

How This Calculator Works

Density is mass per unit volume. This calculator solves for any one of the three quantities - density, mass, or volume - when you know the other two. Pick which variable to find, enter the known values in SI units (kg, m³, kg/m³), and the result appears instantly to six significant figures. It also tells you whether the material floats in water by comparing its density to water's 1,000 kg/m³, and lists reference densities for common materials so you can identify an unknown sample.

Formula

The core relationship is ρ = m ÷ V, rearranged as needed: m = ρ × V to find mass, and V = m ÷ ρ to find volume. Density is reported in kg/m³; note that 1,000 kg/m³ = 1 g/cm³ = 1 g/mL. Specific gravity, a related dimensionless figure, is the material's density divided by water's. An object floats when its density is less than 1,000 kg/m³.

Worked Example

A block with a mass of 5 kg and a volume of 0.005 m³ has density ρ = 5 ÷ 0.005 = 1,000 kg/m³ - exactly water, so it just barely floats. To find the mass of 0.002 m³ of aluminum (ρ = 2,700 kg/m³): m = 2,700 × 0.002 = 5.4 kg. To find the volume of 19.3 kg of gold (ρ = 19,300 kg/m³): V = 19.3 ÷ 19,300 = 0.001 m³.

Common Mistakes

Mixing units - entering grams or cm³ while the field expects kg or m³ throws results off by factors of 1,000.

Dividing by zero volume or zero density - both are physically meaningless and rejected.

Confusing density with weight - density is an intensive property independent of how much material you have.

Forgetting g/cm³ to kg/m³ conversion - multiply g/cm³ by 1,000.

Measuring irregular volume with a ruler - use water displacement instead.

Tips & FAQ

Why does ice float? Its density (917 kg/m³) is below water's 1,000, so it displaces more than its own weight. How do I measure an odd shape? Submerge it and read the displaced water volume - Archimedes' method. What is specific gravity used for? Comparing materials and testing precious-metal purity without units. Does temperature matter? Yes - materials expand when heated, slightly lowering density, so reference values assume standard conditions.

Density Calculator

Frequently Asked Questions

Related Science Calculators